BridgeBio Oncology Therapeutics reported early clinical data suggesting its KRAS G12C inhibitor BBO-8520 may outperform existing drugs in the class.
In the phase 1 Onkoras-101 trial, the company announced a 65% overall response rate (ORR) in second-line KRAS G12C-mutant non-small cell lung cancer based on 17 patients. One response was unconfirmed; excluding that case lowers the ORR to 58%. Those figures compare with ORRs of 36% for Amgen’s Lumakras and 43% for Bristol Myers Squibb’s Krazati in trials supporting their accelerated approvals, and are similar to Revolution Medicines’ reported 56% ORR for elironrasib. BridgeBio cautioned the findings are early and based on small numbers and will need confirmation in larger studies.
BBO-8520 is designed to bind both the active (“on”) and inactive (“off”) states of KRAS G12C, while approved agents target only the off state. BridgeBio says this dual-state targeting could increase potency and reduce required drug levels.
BridgeBio also released initial results for BBO-8520 combined with pembrolizumab (Keytruda). Among eight patients—both treatment-naive and treatment-experienced—five achieved partial responses: three of three in the treatment-naive cohort and two of five in the treatment-experienced cohort (all of whom had prior KRAS G12C inhibitor therapy). Responses were observed across PD-L1 expression levels, including two responses in patients with 1–2% PD-L1. One grade 3 liver enzyme elevation was reported; the company attributed it to co-medications, said the event resolved, and the patient remained on therapy.
Investors appeared encouraged by the update, sending BridgeBio Oncology Therapeutics’ stock up about 4% at Wednesday’s close.
BridgeBio plans another data update in the second half of 2026 and intends to test BBO-8520 in combination with its PI3Kα:RAS breaker BBO-10203.
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